GZMB and neoplasm: Treatment of MB49cPD-L1 tumors in the cPD-L1 mice with either the 12C or 3C antibody significantly reduced the tumor size (Fig. 3F), and increased the number of infiltrating cytotoxic T cells relative to mice treated with control IgG as measured by CD8 and granzyme B expression (Fig. 3G–I).